1. Field of the Invention
The present invention relates to a shock absorbing assembly, and more particularly to a rear shock absorbing assembly for a bicycle, which has a leverage near unity.
2. Description of Related Art
To increase the comfort of riding a modern bicycle, a shock absorbing assembly is always mounted between the frame and the rear wheel of the bicycle. With reference to FIGS. 4 to 6, each of three types of conventional rear shock absorbing assemblies in accordance with the prior art comprises a rear fork (42) and a shock absorber (44). One end of the rear fork (42) is pivotally connected to the frame (40). The rear wheel (not shown) of the bicycle is rotatably mounted on the other end of the rear fork (42). The shock absorber (44) is pivotally connected between the frame (40) and the rear fork (42). Accordingly, when the rear wheel bumps an object, the rear fork (42) will pivot relative to the frame (40) and press the shock absorber (44). The shock absorber (44) can absorb the shock applied to the rear wheel to keep the shock from being transported to the frame (40). Riding the bicycle is more comfortable, and steering the bicycle is also improved.
However, the leverage of the conventional rear shock assembly is in the range of 2.5 to 5, where the leverage is a ratio of the distance between the center of the rear wheel and the pivot between the frame (40) and the rear fork (42) to the distance between the pivot between the rear fork (42) and the shock absorber (44) and the pivot between the frame (40) and the rear fork (42). In another words, when one-unit of force is applied to the rear wheel, there will be 2.5 to 5 units of force applied to the shock absorber (44). As the leverage of the rear shock assembly is increased, the shock absorber (44) must bear a larger force. When the leverage is large, the shock absorber (44) is easily damaged, and the useful life of the shock absorber (44) is reduced.
In addition, to bear a large force, a spring with a high coefficient of elasticity must be used in the shock absorber (44). The weight and the cost of the shock absorber (44) increases.
To overcome the shortcomings, the present invention tends to provide an improved rear shock assembly to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide an improved rear shock assembly for a bicycle, which has leverage near unity to reduce the force applied to the shock absorber. The rear shock assembly has a pair of chain stays, a pair of seat stays, a lever and a shock absorber. The chain stays are pivotally connected to a bicycle frame. A rear fork tip is formed on one end of each chain stay. One end of each seat stay is pivotally connected to one of the rear fork tips. The lever has a center connection point, a first end and a second end. The center connection point of the lever is pivotally connected to the bicycle frame. The pair of seat stays are pivotally connected to the first end of the lever. The shock absorber is pivotally connected between the second end of the lever and one of the rear fork tips. With such an arrangement and compared to the conventional rear shock absorber assembly, the leverage of the rear shock assembly is reduced to nearly unity. The force applied to the shock absorber is reduced. The useful life of the shock absorber is prolonged.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.